JP2704194B2 - Black aluminum nitride sintered body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blackened aluminum nitride (hereinafter abbreviated as AlN) sintered body mainly used for electronic component substrates and the like.

(Prior Art) AlN sintered bodies have attracted attention and have been put to practical use as highly integrated semiconductor package substrates because of their high insulating properties, high thermal conductivity and low dielectric properties. Such Al
A sintered body of N is obtained by adding a small amount of a sintering aid to AlN powder and sintering at a high temperature in a non-oxidizing atmosphere. The AlN sintered body itself is semi-translucent and exhibits a gray to brown hue.

Therefore, when applied as a substrate of a semiconductor package or the like, blackening is required for the purpose of making contaminants in handling during manufacturing less noticeable or of blocking light or the like that adversely affects the element. ing. In response to this requirement, there has been conventionally known a method in which an oxide or a carbide of Group IVa, Va, or VIa in the periodic table is added and fired.

(Problems to be Solved by the Invention) However, in the case of the above-described blackening means, the blackness tends to vary, the electrical characteristics (tan δ and insulation resistance) are not stable, and the surface during the subsequent oxidation treatment is not stable. There is a problem that the condition is greatly affected, etc., and blackening that satisfies all of these problems
Since AlN sintered bodies have not yet been put to practical use, they were present.

(Objects of the Invention) The present inventors maintain high thermal conductivity and high insulation while maintaining high thermal conductivity and high insulation.
As a result of earnest research on blackening the AlN sintered body, a molybdenum compound (especially an oxide) was used as a blackening agent, and a Group IIa oxide and / or a periodic rate table II was used as a sintering aid.
Calcination using Group IIIa oxide, metal molybdenum and / or
Alternatively, it was found that an AlN sintered body having excellent properties and being uniformly blackened can be obtained by forming a molybdenum carbide and simultaneously forming a IIa · Al compound and / or a IIIa · Al compound. Here, the present invention is not provided.

(Means for Solving the Problems) The black AlN sintered body of the present invention, which contains AlN as a main component and metal molybdenum and / or molybdenum carbide as a blackening agent,
A rare earth aluminum compound or an alkaline earth aluminum compound in addition thereto, wherein molybdenum is contained in the sintered body in an amount of 0.01 to 5% by weight in terms of oxide; and a rare earth element is contained in an amount of 0.1 to 15% by weight in terms of oxide. %, And when the composition further contains an alkaline earth aluminum compound, the alkaline earth element is contained in a proportion of 0.005 to 3% by weight in terms of oxide.

The blackening agent used in the present invention exists as metallic molybdenum and / or molybdenum carbide in the sintered body, and the blackening agent in such a form is obtained by converting molybdenum oxide (MoO ₃ ) to AlN.
It is obtained by firing in a medium non-oxidizing atmosphere (molybdenum carbide is obtained by reacting with impurity carbon in the composition together with the reduction reaction). The reason why the content of molybdenum (Mo) is set to 0.01 to 5% by weight in terms of oxide (MoO ₃ )
If the content is less than 0.01% by weight, blackening will not occur, and if it exceeds 5% by weight, the thermal conductivity will be 100 W / mk or less, and the electronic component will not be suitable as a substrate.

In addition, according to the present invention, a rare earth aluminum compound and / or an alkaline earth aluminum compound are present in the sintered body, and the compound of such a form is used as a sintering aid for the rare earth oxide and / or the AlN. When the alkaline earth oxide is added and the firing is performed in the non-oxidizing atmosphere, the rare earth oxide and / or the alkaline earth oxide react with the aluminum oxide and / or impurity oxygen in the AlN. In addition,
In this sintered body, an oxide of rare earth element (Ln) (Ln ₂ O
₃ ) The reason why 0.1 to 15% by weight in terms of conversion and 0.005 to 3% by weight in terms of oxide (AxO) of alkaline earth element (Ax) in the case of further containing an alkaline earth aluminum compound is as follows. That is, when the content of the rare earth oxide is less than 0.1% by weight and / or the content of the alkaline earth oxide is less than 0.005% by weight, the sintered body is hardly densified and blackened, and has a thermal conductivity of 100 W / m2.
When the content of the rare earth oxide exceeds 15% by weight and / or the content of the alkaline earth oxide exceeds 3% by weight, the thermal conductivity becomes 100 W / mk or less. Desirably, by setting the rare earth oxide content to 0.5 to 12% by weight and the alkaline earth oxide content to 0.01 to 1.5% by weight, higher thermal conductivity is obtained and sinterability is improved.

As the rare earth aluminum compound, Ln ₃ Al ₅ O ₁₂ , LnAlO ₃ , Ln ₄ Al ₂ O ₃ (however, Ln; Y, Gd, Dy, Ho, Er, Yb) is desirably employed.

As the alkaline earth aluminum compound, AxAl ₂ O ₄ , AxAl ₄ O ₇ , AxAl ₁₂ O ₁₉ (however, Ax; Ca, Sr, Ba) are desirably employed.

The aluminum nitride sintered body of the present invention can be manufactured by a known method. More specifically, AlN
After blending and mixing the powder, sintering aid and blackening agent,
Molding is performed by a known molding method, for example, press molding, injection molding, doctor blade method, and the like, followed by firing. The firing is performed at a temperature of 1500 to 2000 ° C. in a non-oxidizing atmosphere containing nitrogen by normal pressure firing, hot press firing, gas pressure firing, HIP firing, or the like.

The AlN raw material powder used has an impurity oxygen content of 2.5%.
Weight% or less, average particle size 1.5 to 2.5 μm, cationic impurities
It is suitable that the content is 1% by weight or less, and that the sintering aid and the blackening agent have an average particle size of 0.5 to 5.0 μm.

(Action) The black AlN sintered body having the above-described structure has a predetermined amount of the metal molybdenum and / or molybdenum carbide. In addition, the sintered body becomes extremely dense and robust due to the presence of the specified amount of the rare earth aluminum compound and / or the alkaline earth aluminum compound, and furthermore has a large thermal conductivity and is adequately suitable as an electronic component substrate or the like. Becomes

(Examples) Next, the present invention will be described in more detail with reference to Examples.

(A) an impurity oxygen amount of 1.2% by weight or less, an average particle size of 1.5 μm,
AlN with less than 0.1% by weight of cationic impurities except aluminum
The powder, sintering aid (oxide) powder having a particle size of 0.5 to 5 μm, and blackening agent powder (MoO ₃ ) were weighed and mixed so as to have the composition shown in Table 1, and then granulated and press-molded. The sintered body was fired at 1820 ° C. for 3 hours in a non-oxidizing atmosphere in a nitrogen stream to obtain a test piece of a sintered body. In Table 1, the remainder other than the sintering aid and the blackening agent is all AlN.

(B) For the test piece of the sintered body obtained above, the degree of blackening was visually determined, and the thermal conductivity was measured by a laser flash method, and the specific resistance was measured using a disk. The crystal phase of the additive was identified by XRD. Table 1 shows these results together with the composition ratio and the like.

From the results in Table 1, it can be seen that Samples Nos. 1 to 20 all exhibit good blackness, have excellent thermal conductivity, and exhibit a specific resistance suitable for a substrate such as a semiconductor package. Compared to these, Sample No. 21 was not sufficiently blackened because the amount of the blackening agent was small, and Sample No. 22 was low in thermal conductivity and specific resistance value because the blackening agent was too much. Sample N
o.23 and 25 did not sinter due to the small amount of sintering aid, and the thermal conductivity was extremely low, while samples Nos.24 and 26 had too much sintering aid, The rate dropped. Sample N
In Nos. 27 and 28, the blackening agent was other than metal molybdenum or molybdenum carbide, and therefore, sufficient blackness was not obtained.

(Effect of the Invention) As described above, the black AlN sintered body of the present invention is excellent in blackness, has less variation, and has a high thermal content by containing a blackening agent and the like in the specified amount as specified above. It has high conductivity and excellent electrical characteristics, and also has excellent characteristics in the surface state during the subsequent oxidation treatment, and has excellent suitability as a substrate for a highly integrated semiconductor package or the like.

The usefulness of the black AlN sintered body of the present invention having such remarkable performance is extremely large.

Claims (2)

(57) [Claims] 1. A sintered body containing aluminum nitride as a main component, a rare earth aluminum compound, and a metal molybdenum and / or molybdenum carbide as a blackening agent, wherein the rare earth element is converted into an oxide in the sintered body. A black aluminum nitride sintered body containing 0.1 to 15% by weight in terms of conversion and 0.01 to 5% by weight in terms of oxide as molybdenum. 2. The black aluminum nitride sintered body according to claim 1, further comprising an alkaline earth aluminum compound, wherein the alkaline earth element is converted into an oxide in the sintered body.
A black aluminum nitride sintered body, which is contained at a ratio of 0.005 to 3% by weight.